Abstract: A checksum is calculated on a database stored in a SIM card when changes are made to a database stored therein. This checksum can be stored in a mobile phone, e.g., with the change log. When synchronization between devices is to be performed, another checksum can be calculated on the database stored in the SIM card. If the stored checksum does not match the calculated checksum, then a change has occurred in the contents of the database that is not reflected in the change log. Accordingly, a full synchronization process can be performed wherein the database records in each device can be compared. If, on the other hand, the checksums match, then the change log accurately reflects any changes made to the database stored in the SIM card and the synchronization process can proceed more expediently using the change log.

Abstract: A technique for securely storing data within a memory is disclosed. In a preferred embodiment, the technique is realized by encrypting the data using a non-verifiable personal identifier, and then encrypting a reminder using the same non-verifiable personal identifier. The encrypted data and the encrypted reminder are then stored in the memory. The stored encrypted data and the stored encrypted reminder can only be correctly decrypted using the non-verifiable personal identifier. Also, a correctly decrypted reminder provides an indication of correctly decrypted data. The non-verifiable personal identifier is not stored in the memory so as to insure security of the system.

Abstract: A method, system, and apparatus enables an electronic device in communication with an accessory to accurately report a remaining battery life when the accessory provides information relating to a power usage to the electronic device. In one embodiment, the accessory draws power from a battery of the electronic device, and the electronic device is able to more accurately estimate a remaining battery life by considering the power usage information provided from the accessory. The electronic device may thereafter indicate to a user the remaining battery life. In one alternative of this embodiment, the information relating to the power usage is in the form of a current consumption of the accessory. In another embodiment, the electronic device indicates a remaining battery life of a battery of an accessory.